Process for producing level dyeings on polyamide fibers



PRUCESS FOR PRODUCING LEVEL DYEWGS 9N PQLYAMIDE FIBERS Harold -C. Gift, Temple, and Lawrence P. Procter, Woinclsdorr, Pa, assignors to Crornpton 8: Knowles Corporation, Worcester, Mass, a corporation of Massachusetts 4 No Drawing. Filed Mar. 9, 1962, Ser. No. 178,581

9 Claims. (Cl. 8-55) This invention relatesto a method of dyeing natural and synthetic polyamide fibers (e.g., wool,-si1k, nylons,

" etc.) having variable dye affinities so as to provide level dyeings which also have satisfactory fastness properties. The invention is particularly useful in connection with the dyeing of textured nylons, deep dye nylons and especially combinations of such fibers with regular polyamidefibers where a very high differential of dye afiinity exists between the fibers forming the combination.

Another aspect of the invention is concerned with dyeing of nylons in combination with cellulosic materials A United-States Patent ties. -These property variations are chiefly caused by dif- Iferences in molecular, orientation and the degree of polymerization. Density is one of the mostcommon proper ties whichwill vary"- over arelatively. widerange, and density variations in turn, appear to be :related insome way to the varying affinity that the polyamide fibersexhibit for dyes. .Heretofore, the

l amideifibershas beenof such.-a magnitude that it hasi.

precluded, obtaining. level (iuniforrnity as to shade and depth) 'dyeings with dyes'of-the type which also would variable dyeing alfinity ofjthe polygive. a satisfactory dcgree ofifastne'sstr'om the stand-" point. oi; light, water, washing, sublimation and .crocking- I In otherwords with, certain dyesnarnely, the so-called .45

neutral acid dyes ahigh degree of'fastness could be 1 obtained but,the dyeing would not be -l evel.- Conversely,

with other dyes (e.g., the dispersed, type dyes) level dyeings could beiobtained" but onlyfby sacrificing iastness properties. I 7

, By the present the known desirable fastness properties jofithis class of dyesm fastness propertieswhich method involves passing the. fibers through an aqueous dye bathhich contains. a

invention, a process has been provided which will permit theme of water soluble neutral dyeing ;dye-stults,]such asljthe" acid dyes, neutral acid dyes. "and the neutral premetallized' acid dyes for the dyeing of polyami'de fibers soas to produce level dyeings having materials such as wool, silk, nylons and the like. The

fibers can be in any form which is convenient for handling such as staple form, continuous filaments, yarns, threads, or in any of the many forms known to the textile industry and especially as warp, woven, tufted or knitted fabrics, lace in the piece and similar finished or semi-finished yarn products.

Suitable dyes for use in accordance with the present invention are the so-ca1led acid dyes for polyamide fibers which are soluble in water. Such dyes include the acid dyes, neutral acid dyes and the neutral premetallized acid dyes. Typical acid dyes for use in the invention include the monoazo, diazo and anthraquinone dyes which contain water solubilizing groups such as Acid Yellow 40 (CI. 18950), Acid Red 114 (CI. 23635), Acid Blue 27 (CI. 61530) and dyes of the type disclosed-in the copending application owned by applicants 'assignee Se rial No. 75,112, filed December 12, 1960, are also use- 111 for providing red and scarlet shades. Such dyes are capable of dyeing nylons under either acid or substantially neutral conditions depending on the dye aflinity' of the particular fiber involved. Typical neutral'premetallized acid dyes include dyes having a 2:1 dyemetal complex suchas Acid Yellow 114, Acid Orange 60, Acid Red 182 and Acid Brown 28 (Cl. designations).

howeven a continuous pad bath is generally considered o e mo t, a s a t ry.v .In Pa s the fabric through; the padder, the temperature of the bath should be main-j tainedbelow about 90 and preferably at roomtemperature.. The material shouldbe passed through the bath at a rate such that little or no substantial dyeing occurs.

Ifthetemperature is much in excess of 90 F., there will .fbe some dyeing 'Of'thernateriaI comingoutjof the pad bath andpin accordance with the}. 'present invention, dye iiig at thisfstage of the operation is to be avoided; The,

object of this operation merely beingto applya surface coating. of the dye' 'tothe fibrous material and to remove I the material from the pad bathbefore any substantial degree of dying occurs."

After the dye liquor has'been applied to the material, the excess liquor 'can be-removedbylanyconventional means such as squeezing, suction, extraction andfthe like or by a combination-oi suchmeans 'e.g., squeezing; and suction. In this waygauniforrn distribution of the dyeion thesurface of ,the jrnaterial is obtained.

By employinga cold dye solution, the dyeing aifinit y is I thereby minimizedand the desired uniform distribution of 1 the dyesion thesurfa'ce can be eflected before actual dye-r T ing commences.

' The'dye bathinade:in'accordance withgthe present in vention should be-substantially neutral (apHof about 16.5 to;8.5 and'preferably'at'a'pH-ofj to 8) 'andjshould also contain an organic swelling'agent for-theffibers in which the dye is"-soluble.- Asuitable: groupof' swelling 'a'g'ents' for use in accordance with the inventiomare the lower 1' alcohols such asjisopropanol, methanol; ethanol: and other water soluble neutral dyeing dye forsuch fibers and an organic swelling agent for the fibers inwhich the dyeiis soluble. During the dye application operatiompthe dye-- bath is maintained at temperatures below about 90 F. After the fibers have been removed'from the dye' bath they are steamed under conditions comparable tothose providedby athree minutesteam treatment at atmospheric pressure e Suitable polyamide fibers the present invention includes-both naturaland synthetic t -f70, for use' in' accordance-with g'bath and tofacilitate the .wetting of the fibers. The swellreadily water soluble; alcohols.

obtainedwith as little as 10% of the :alcohol. An upper limit of about 30% is prescribed but only because of the economicsdnvolved a solvent ,recovery system is eco- Patented Panza, 1965.

p Because of ,itsj: 'higher boiling'point and lowertoxicity, ,it is-prefer'red toiemployf ;isopropyl alcohol, Further, it is preferred to employ'dye fbaths; which contain about 20% 0f alcohol (methan L ethanol or isop'ropanoly' However, level dyeings can be hada pH of 7.5 and was made up as follows:

ing agents also enable the dye to thoroughly penetrate the fiber during the subsequent dyeing operation.

The dye baths may also include thickeners such as carboxy methyl cellulose, alginates, etc. which are soluble in the dye liquor; and where such thickeners are used, they will increase the dye solution pick-up of the fibers undergoing treatment.

After the application of the dye from the cold dye bath, the material is steamed for a minimum of three minutes at atmospheric pressure or for an inversely proportionate length of time at elevated steaming pressures. During the steaming operation, dyeing takes place. The steaming operation appears to cause even greater swelling and permit deep uniform penetration of the dye into the fiber. On the other hand, dry heat at this stage, does not enable the dye to penetrate deeply or uniformly and will give a marked differential in shade and depth of dyeing.

After steaming, the material is dried and followed by rinsing or Washing, if necessary. In most cases, subsequent rinsings or washings are not essential as the dyes are deeply penetrated into the fibers themselves.

The following examples will serve to illustrate how the invention may be carried out:

Example #1 Textured polyamide fabric was entered in a dye bath (pH 7.5) at room temperature (70 F.) made up as follows with neutral dyeing acid colors:

Percent Acid Yellow 40 (CI. 18950) 0.25 Acid Blue 27 (Cl. 61530) 0.16 Acid Red 114' (C1. 23635) 0.01 Carboxy methyl cellulose 0.3 Isopropyl alcohol 20 Water to 100%.

The dyeing shows excellent coverage of the polyamide fibers, far superior to machine dyeing, while thefastness to light, washing sublimation and crocking are excellent.

By using alcohol in the dye solution, no appreciable differences were noted.

Example #2 Carpeting composedof tufted textured polyamide fibers and having a jute backing was padded through a solution of'neutral acid colors at room temperature. I The solution Percent Acid Blue 27 (CI. 61530) 0.9v Acid Yellow.40 (C.I. 18950) 0.1 Acid Red 114 (CI. 23635) 0.2 Carboxy methyl cellulose 0.3 Isopropyl alcohol 20.0

Water to 100%.

The treated carpeting was run through squeeze rolls with minimum pressure, then over asuction plate. (it can be run either face or back down) adjusted to give 62% solution retention based on-the'weight of the fabric, and then steamed for three minutesat atmospheric.pressure and dried.

This dyeing'provided excellent coverage on the poly amide fibers and the jute was dyed to an acceptable match for depth and shade. The light fastness, water stability,

crocking and sublimation fastness were excellent.

Example #3 A. fabric composed of the so-called Deep Dye textured polyamide fibers (Chemstrand Corporation) in combination with regular textured polyamide fibers was dyed by immersing the fibers in a neutral solution of:

Percent Acid Yellow 40 (CI. 18950) 0.25 Acid Blue 27 (CI. 61530) 0.18 Acid Red 114 (C.I. 23635) 0.01 Carboxy methyl cellulose 0.3 Isopropyl alcohol 20.0

Water to 100%.

The fibers are immersed in this solution at room temperature, extracted before any significant dyeing had occurred, and then steamed at atmospheric pressure for three minutes and dried.

Both types of fibers were dyed to an acceptable union and with excellent fastness to light, washing, sublimation and crocking.

Example #4 Example 1 was repeated except that no thickener (the carboxy methyl cellulose) was used in the pad bath. The results were identical except that the depth of shade was substantially reduced.

In all of the foregoing examples, the fabric was entered into and removed from the dye bath before any substan-m tial degree of dyeing had occurred.

We claim:

1. A process producing level dyeings on polyamide fibers which comprises passing the fibers through an aqueous bath having a pH of about 6.5 to 8.5 containing a water soluble neutral dyeing dye for such fibers and an organic swelling agent for the fibers in which the dye is soluble, maintaining the bath at a temperature below about 90 F., removing the fibers from the dye bath before any substantial degree of dyeing occurs and thereafter subjecting the treated fibers to steaming under conditions.comparable to those obtained by about a 3-minute steam treatment at atmospheric pressure.

2. A process for dyeing polyamide. fibers which comprises passing the fibers through an aqueous bath having a pH of about 6.5 to 8.5 containing a water soluble dye selected from the group consisting of acid dyes, neutral acid dyes and neutral preme'tallized acid dyes, and an organic swelling agent for the fibers in whichthe dye is soluble, maintaining the bath at a temperature below about 90 F;, removing the fibers from the dye bath before any substantial degree'ofdyeing occurs and thereafter subjecting the treated fibers to steaming under conditions at least comparable to those obtained by a 3-minute treatment at atmospheric pressure.

3. A process according to claim 2 wherein the swelling agent is a water soluble alcohol. I

4. A process according to claim 3 'wherein the alcoholhonstitutesfrom-about 1'030% of the dye bath and contains from oneto three carbons.

5. A process producing level dyeing on polyamide fibers having variable dyeing afiinity which comprises 1 passing the fibers through an aqueous bath having a pH of about 6.5 to 8.5 and containing a water soluble neutral dyeing dyestuff for such fibers and an organic swelling agent for the fibers in which the dye is soluble, maintaining the bath at a temperature below about 90 F., removing the fibers from'the dye bath before any substantial degree of dyeing occurs, and thereafter subjecting the treated fiberstosteaming under conditions comparable to those obtained by abouta 3-minute steam 'treatmentat the poly- 5 6 jute fibers which comprises treating the fibers according 2,683,647 7/54 Hagan 8-55 to claim 5. I 2,888,313 5/59 Mautner 854 2,890,094 6/59 Tucker 854 References Cited by the Examiner 051 541 2 Clapp g 4 UNITED STATES PATENTS 5 3,112,983 12/63 Collins 8-54 2,447,993 8/48 Vieira 8-34 2,469,695 I 5/49 McNauy et a1. NORMAN G. TORCI-IIN, Przmary Exammer.

2,487,197 11/49 Stott et a1 8--34 ABRAHAM O. WILKELSTEIN, Examiner. 

1. A PROCESS PRODUCING LEVEL DYEINGS ON POLYAMIDE FIBERS WHICH COMPRISES PASSING THE FIBERS THROUGH AN AQUEOUS BATH HAVING A PH OF ABOUT 6.5 TO 8.5 CONTAINING A WATER SOLUBLE NEUTRAL DYEING DYE FOR SUCH FIBERS AND AN ORGANIC SWELLING AGENT FOR THE FIBERS IN WHICH THE DYE IS SOLUBLE, MAINTAINING THE BATH AT A TEMPERATURE BELOW ABOUT 90*F., REMOVING THE FIBERS FROM THE DYE BATH BEFORE ANY SUBSTANTIAL DEGREE OF DYEING OCCURS AND THEREAFTER SUBJECTING THE TREATED FIBERS TO STEAMING UNDER CONDITIONS COMPARABLE TO THOSE OBTAINED BY ABOUT A 3-MINUTE STEAM TREATMENT AT ATMOSPHERIC PRESSURE. 